HPLC Determination of Flavonoid Glycosides in Mongolian Dianthus versicolorFisch. (Caryophyllaceae) Compared with Quantification by UV Spectrophotometry

Introduction Dianthus versicolor is used in traditional Mongolian medicine against liver impairment. Fractions enriched in flavone-di- and triglycosides were shown to enhance bile secretion. Therefore, reliable and accurate analytical methods are needed for the determination of these flavonoids in the crude drug and extracts thereof. Objective To provide a validated HPLC-DAD (diode array detector) method especially developed for the separation of polar flavonoids and to compare the data obtained with those evaluated by UV spectrophotometry. Methodology Separations were carried out on an Aquasil® C18-column (4.6 mm × 250.0 mm, 5 µm) with a linear gradient of acetonitrile and water (adjusted to pH 2.8 with trifluoroacetic acid) as mobile phase. Rutoside was employed as internal standard with linear behavior in a concentration range of 0.007–3.5 mg/mL. Accuracy was determined by spiking the crude drug with saponarin resulting in recoveries between 92% and 102%. Results The method allows the quantification of highly polar flavonoid glycosides and the determination of their total content. For saponarin a linear response was evaluated within the range 0.007–3.5 mg/mL (R2 > 0.9999). It was proven that threefold sonication represents a time-saving, effective and cheap method for the extraction of the polar flavonoid glycosides. The contents determined by HPLC were shown to be in agreement with those obtained employing UV spectrophotometry. Conclusion The study has indicated that the newly developed HPLC method represents a powerful technique for the quality control of D. versicolor. Ultraviolet spectrophotometry may be used alternatively provided that the less polar flavonoids are removed by purification. Copyright © 2011 John Wiley & Sons, Ltd.